The processing of taste stimuli by the peripheral gustatory nervous system will be studied. The primary method used is electrophysiological recording from single neurons in the hamster (Mesocricetus auratus) chorda tympani, the nerve that innervates taste buds on the anterior tongue. Stimulus parameters for three physiologically defined populations of nerve fibers will be determined for single compounds and binary and ternary mixtures of taste stimuli. The effects of specific ion channel blockers, applied immediately before or mixed stimuli, will address the roles of Na+, K+, Ca++, and anion channels in stimulus reception and transduction. Responses of the nerve fibers to mixtures of stimuli will be studied to establish mechanisms of mixture interaction such as suppression or synergism in each population of nerve fibers. Chemically diverse "sweeteners" will be studied pairwise by neural cross-adaptation and behavioral cross- generalization to address whether they stimulate distinct "neural activation" process and are discriminable. Cross-generalizations in hamsters lacking taste information carried by the facial nerve from the anterior tongue and palate will be studied to identify the roles of different taste nerves in perception of "sweeteners". These experiments are expected to help establish basic mechanisms involved in chemoreception and neural processing of chemosensory information. Three different levels of inquiry focus on the contribution of receptors, primary afferents, and cranial nerves to the coding of gustatory quality and intensity. Understanding of processing of taste stimuli may lead to the control of sugar and sodium ingestion, which contributes to common health problems.